1. Field of the Invention.
The present invention relates to a pressure infusion device, particularly one with an improved gauge for measuring the pressure within a pressure chamber of such a pressure infusion device.
Various liquids for infusion into the body, such as a saline solution, whole blood and plasma, are normally supplied in disposable sterile sealed bags or receptacles of flexible plastic material having an outlet adapted to be punctured by a coupler connected to it, the liquid in the bag being supplied by a delivery tube to the desired region of the body. Such bags are commonly referred to as I.V. bags. In normal use, such as I.V. bag is suspended above the patient and the liquid is permitted to flow by gravity. Often, however, it is desired to speed up the delivery of liquid and in such a case, the bag of liquid is subjected to a source of pressure which maintains the liquid under pressure and speeds up the delivery of liquid. Another use for the application of pressure is to administer fluid to arteries where the pressure in the artery exceeds the pressure which can be generated by merely suspending a bag and relying upon the pressure of gravity. This has been commonly done by providing a second container in the from of a pressure bag which is held in engagement with the sealed bag to apply pressure thereto. The pressure is normally applied by pumping air into the pressure bag. In order to determine what pressure is being applied, it is customary to use a gauge connected to a tube connected to and projecting from the bag or a gauge which is connected to the tube extending between the pump and the bag. A typical gauge is a circular gauge having a movable pointer.
A typical device of the type just described is shown in the Hinck et al U.S. Pat. No. 4,090,514. In many instances, the bag for applying pressure to the sealed liquid bag is a bag which is of a permanent nature and which must be cleaned and sanitized after each use. The cost of cleaning and sanitizing such a bag is relatively substantial. Furthermore, these pressure applying devices are of limited life and are relatively expensive.